How do I tell if my Leo is gravid?

[Spotty Tails]

I recently got 2 female adults that were housed with males about a month and a half ago. Both females have shed, seem happy etc. Now one of them has darkened, getting a little fat, maybe eating all the mealworms. The animal was much brighter when I got her. Their appetites have shrunken quite a bit. I can't find any solid answers on why she has darkened. She/they are not eating much at all. They are less active but I am new to Leos so maybe thats just Leos. (No trouble signs yet). I have them in a 20g long with tile, UTH, thermostat set at 90 degrees F, and 4 hides (one is humid)

 

[DrCarrotTail]

Are you using a quality vitamin and mineral supplement? Could they have gotten cold for a while? Those are the two most common reasons I find geckos darken but any stress can cause a color change. If she is ovulating her color may get a bit darker but the colors of my geckos don't usually seem to really fade until after they lay a clutch or two. It also could just be natural color change as they age. As long as she is eating and healthy I wouldn't worry about it a whole lot.